Pro-Corn - O&P Library

Figure 3C. Typical forefoot deformities of rheumatoid
arthritis—hallux valgus and dorsal dislocation
of metatarsalphalangeal joints (plantar
view).
Figure 3D. Typical forefoot deformities of rheumatoid
arthritis—hallux valgus and dorsal dislocation
of metatarsalphalangeal joints (lateral
view).
physical exam by watching the patient in a
standing position. In addition to the elevated
longitudinal arch, heel varus may be noted.
Plantar flexion of the first ray may be present
and can be seen by viewing the foot anteriorly
with the patient seated. Stabilize the calcaneus
in alignment with the tibia and note the level of
the plantar aspect of the first metatarsal head
relative to the others. The patient with metatarsalgia
secondary to pes cavus may benefit from
a soft arch support to increase the weight
bearing surface of the foot and to improve
shock attenuation.
Ankle Instability
Ankle instability may be the result of lateral
ligamentous laxity, a varus heel, or a varus angulated
tibia. 4
A patient with lateral ligamentous
laxity of the ankle may give a history of
having initially sustained an ankle sprain secondary
to significant ankle trauma followed by
recurrent sprains with minimal or no trauma.
The wearing of high heeled shoes worsens the
tendency of recurrent ankle sprains as this further
throws the foot into supination.
Ligamentous laxity causing ankle instability
can usually be demonstrated by the "lateral
talar tilt" test. The ankle is stress tested both in
dorsiflexion, to test the calcaneofibular ligament,
and in plantarflexion, to test the anterior
talofibular ligament. The tibia is held stationary
as the examiner applies pressure on the lateral
aspect of the hindfoot in a medial direction
(Figure 4). The ankle, which lacks adequate
ligamentous support, will tilt medially indicating
instability.
The presence of heel varus can be appreciated
by viewing the patient from behind as he
stands with shoes removed. It will be noted that
the calcaneous is medial to the longitudinal axis
of the tibia. Upon manipulation of subtalar
joint motion, there may be decreased eversion
of the calcaneous relative to inversion.
A person who had a varus angulated tibia,
either from a congenital deformity or secondary
to a tibia fracture which has united in varus,
may also experience ankle instability. With
such malalignment, the biomechanical forces
pass lateral to the center of the calcaneous. Observing
the standing patient from the front, the
examiner will note that an imaginary plumb
line dropped from the center of the patella will
fall lateral to the center of the ankle on the affected
side.
A lateral heel and sole wedge tilts the hindfoot
into slight valgus to help prevent recurrent
ankle instability.